9 cards are dealt to three people at random, so that everyone gets 3 cards. What is the probability that everyone gets a red card?
Reds(A,B,C) Blue(A,B,C). yellow(A,B,C)
If we were to randomly arrange the cards such that the first 3 cards would be for the first person and so on, there would be 9! ways to do so.
Now, if we were to distribute the 3 red cards such that each person gets one, there are 6 ways that could happen. Then, we can distribute the remaining 6 cards using the same above method to get 6! ways.
That means the final probability is 6*6!/9!=1/84
:D